Landover, MD., September 19, 2005 -- The Epilepsy Foundation working group of experts on photic- and pattern-induced seizures today released its
recommendations for preventing seizures provoked by dynamic light and imaging sources such as television, videogames, websites, motion pictures and other media. The consensus recommendations cover factors, such as light intensity, flicker, contrast, duration and pattern, and the technical parameters within these factors that are most likely to provoke seizures in susceptible individuals. They are reported in the September issue of the journal
Epilepsia. Accompanying the report is an article on the literature and data review conducted for the working group as part of its analysis and development of recommendations.
The Epilepsy Foundation believes that seizures from visual stimulation represent a significant public health problem. While the risk to susceptible individuals cannot be eliminated by the current level of knowledge, recent research of photosensitivity has resulted in the accumulation of sufficient knowledge to develop educational programs and procedures to substantially lower the risk for this type of seizure. The working group was convened by the Epilepsy Foundation in cooperation with the Centers for Disease Control and Prevention to develop the photosensitivity related recommendations for possible use by industry.
According to the group’s review of available data, the annual incidence of visually provoked seizures in the United States general population is estimated to be one in 91,000. Among young people 7 to 19 years of age – a population that is most susceptible to these provoked seizures and among the most frequent users of video technology – the annual incidence may be five-times as high, or one in 17,500. Only individuals who are susceptible, meaning who are photosensitive, are at risk for developing seizures provoked by light. There is no evidence that exposure to television, videogames or other light and image-producing technology is a cause of epilepsy, they report.
Interest in photosensitivity, the susceptibility to altered brain wave activity when the visual system is exposed to certain types of stimulation, seizures and other potential symptoms in response to light flicker and/or pattern, has increased in recent decades with early reports of incidents among television viewers and later among young people playing videogames. Many epileptologists (doctors who specialize in treating seizures) have also observed that some of their young patients have experienced seizures only when exposed to specific visual media and at no other time. Concern over these incidents increased dramatically in December 1997 when a Pokemon cartoon on Japanese television sent nearly 700 children to the hospital with various symptoms, including ~500 children who had seizures.
Within variations due to gender, age and other factors, about 0.3 – 3.0 percent of the general population is photosensitive, meaning that their EEG (brainwaves) show abnormal reactions to certain flicker frequencies or periodic patterns. Only a fraction of those showing abnormal photosensitivity will have light-induced seizures in real life. Risks are higher among individuals known to have epilepsy, especially certain types such as idiopathic generalized epilepsy, and juvenile myoclonic epilepsy. The authors report that, “With the exception of flashing fire alarms, there are no recommendations, guidelines, standards, regulations or rules in the United States that specifically address the issue of photosensitivity.” The recommendations in the Epilepsia report can be applied not only in the development of television programming, but to the full range of visual media to which the public might be exposed.
The consensus group was composed of medical researchers with expertise in photosensitivity from Great Britain and Japan who had aided officials in developing guidelines specific to the television industry in their countries, and several leading US epileptologists. Information and perspective from industry and the standards and regulatory sectors in the US were provided by representatives of the Federal Communications Commission, US Access Board, US Consumer Products Safety Commission, the Consumer Electronics Association, attorneys working on the issue, and a representative from the videogame industry.
In their recommendations report, Graham Harding of the Clinical Neurophysiology Unit, Aston University, Birmingham, England, and colleagues, point out that videogame dynamics present a special challenge. The principles they recommend, “Are easier to apply in the case of fixed media, for example, a pre-recorded TV show, which can be analyzed frame-by-frame. Interactive media, such as videogames, may afford essentially limitless pathways through the game, depending upon user actions. Therefore, the working group recognizes that in the case of videogames the consensus recommendations apply to typical pathways of play, but cannot cover every eventuality of play.”
According to the review article, whose lead author is Robert S. Fisher of the Department of Neurology and Neurological Sciences, Stanford Medical Center, Stanford, CA, photosensitivity remains little understood. Genetic factors are clearly involved but neither their role nor the genes involved have been identified. More research is also needed to explore other factors, such as color, that might be involved on provoking seizures, and to further elucidate technical parameters described in the Epilepsy Foundation’s working group recommendations.
Coincident with the published report, the Foundation has also released a set of recommendations developed by members of the working group as guidance for families in limiting their risk of visually provoked seizures, and for recognizing signs indicating a potential sensitivity to visual stimulation. The
recommendations are available on the organization’s website –
www.epilepsyfoundation.org – or by calling (800) 332-1000.
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The Epilepsy Foundation, a national non-profit with affiliated organizations throughout the United States, has led the fight against epilepsy since 1968. The Foundation's goals are to ensure that people with seizures are able to participate in all life experiences; and to prevent, control and cure epilepsy through research, education, advocacy and services. For additional information, please visit
our website.
